Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001)
Irregular/uneven, Uneven
(Zn,Mn2+ ,Fe2+ )(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)
Ca 2Al 3(SiO 4) 3(OH)Walter Schumann , Gemstones of the world (2001) More from other references